Atomic models: Dalton to quantum in 3D
Follow the evidence from solid spheres to electron probability. Explore the 3D model, inspect its parts and learn with guided explanations. Free on Atlas.
What you can learn
Follow the evidence from solid spheres to electron probability.
Start with the chemical atom.
Add the electron to the story.
Ask what could deflect an alpha particle.
Try an investigation
Start with the chemical atom. Then compare thomson model with rutherford evidence. Explain what the visible structures show and what the model leaves out.
Check your understanding
Why was Dalton’s atom revised?
Evidence showed internal particles. Evidence showed internal particles. Dalton’s model treated atoms as indivisible units of elements. The golden sphere represents that historical idea. Later discoveries revealed internal charged particles, so the sphere is a starting point in the story rather than today’s complete model.
An empty Bohr ring represents…
Another allowed state. Another allowed state. The Bohr hydrogen example has one electron marker and several allowed orbit guides. Empty rings represent alternative states. Their radii are compressed for readability; this historical picture works best for one-electron systems and does not replace modern quantum mechanics.
The modern cloud represents…
A position probability distribution. A position probability distribution. The purple cloud samples a hydrogen 1s probability distribution. Its 1,000 marks represent possible positions from repeated measurements of one electron. They are neither 1,000 electrons nor a trajectory, and the enlarged nucleus shares no true length scale with the cloud.
Sources and model scope
Historical comparison: Dalton, Thomson, Rutherford, Bohr and a modern hydrogen 1s probability distribution. Schematics are not photographs. Atomic and nuclear dimensions are not on a common scale.